The artificial acetabular joint replacing device of the prior art is generally composed of a femoral stem and an acetabular cup, as exemplified by the acetabular joint combination system of the Zimmer Corporation of the United States. Such a conventional device as described above is defective in design in that the femoral stem often fails to join intimately with the femur to which the femoral stem is fastened, thereby resulting in a gradual descent of the femoral stem. Such a surgical mishap often calls for another aggravating surgical operation in which a new acetabular joint combination system is set in place.